Rotary timer with electromagnet biasing contact arm against slotted cam



Sept. 14, 1965 MlTlTAKA YAMAMoTo 3,206,566

ROTARY TIMER WITH ELECTROMAGNET BIASING CONTACT ARM AGAINST SLOTTED CAM Filed Aug. 7, 1961 5 Sheets-Sheet 1 JVlgAV I@ Sept. 14, 1965 MITITAKA YAMAMoTo 3,206,566

ROTARY TIMER WITH ELECTROMAGNET BIASING CONTACT ARM AGAINST SLOTTED CAM Filed Aug. 7, 1961 5 Sheets-Sheet 2 Sept. 14, 1965 MlTlTAKA YAMAMOTO 3,205,565

ROTARY TIMER WITH ELECTROMAGNET BIASING CONTACT ARM AGAINST SLOTTED CAM Filed Aug. '7, 1961 5 Sheets-Sheet 3 JPL/77a) Sept. 14, 1965 Ml'rlTAKA YAMAMOTO 3,206,566

ROTARY TIMER WITH ELECTROMAGNET BIASING' CONTACT ARM AGAINST SLOTTED CAM Filed Aug. 7, 1961 5 Sheets-Sheet 4 Fie/g4, .94,

SeP- 14, 1965 MITITAKA YAMAMoTo 3,206,566

ROTARY TIMER WITH ELECTROMAGNET BIASING CONTACT ARM AGAINST SLOTTED CAM Filed Aug. 7, 1961 5 Sheets-Sheet 5 Fig/L Jiu,

United States Patent O 3,206,566 ROTARY TIMER WITH ELECTROMAGNET BIAS- ING CONTACT ARM AGAINST SLOTTED CAM Mititaka Yamamoto, Ukyo-ku, Kyoto-shi, Japan, assignor to Tateishi Denki Kabushiki Kaisha, Kyoto-shi, Japan, a joint-stock company of Japan Filed Aug. 7, 1961, Ser. No. 129,662 Claims priority, application Japan, Dec. 29, 1960, 35/51,655; May 9, 1961, 36/23,202 4 Claims. (Cl. 200-38) This invention relates to electrical relays, and more particularly it relates to a new and improved time limit relay or timer device requiring a relatively low-power motor and having highly desirable operational characteristics.

In general, in the relay actuating mechanism of a time limit relay, a micro switch or other switch having snap action has been used as the contact, a pin or an eccentric cam has been provided on the rotating shaft of an indicating pointer, and by means of this pin or eccentric cam, a push button has been directly pushed, or the aforesaid switch has been actuated by way of an operating lever. In the case of this type of mechanism, however, since the switch is actuated by the driving power of a synchronous motor, a synchronous motor of a high driving power is necessary, and resulting high loads are imposed also on the rotating parts such as gears, gear shafts, and bearings, thereby shortening the operational life of such mechanisms.

Conventional time limit relays of the reset type have had further disadvantages as described below. In such relays, the gear mechanism is generally driven by a synchronous motor, and a contact device such as a micro switch is actuated, after a predetermined time delay, by a cam mechanism or a lever mechanism by way of an electromagnetic clutch, the other electrical equipment being electrically controlled by the contacting action of the said contact device. At the same time, the synchronous motor is cut oit by another contact from the power source and is stopped, and the actuating condition of the said contact device is maintained. Next, the electromagnetic clutch is demagnetized de-energized by means of current being cut off, whereby the indicating pointer is returned to a predetermined position by such a device as a spiral spring. At the same time, the said contact device is also returned to its original condition, enabling the setting of the time delay. Furthermore, together with the demagnetization of the electromagnetic clutch, its operational condition is returned to that before operation.

In such a time limit relay of the reset type, it has been the conventional practice to use a micro switch for the contact device, and to actuate the micro switch by applying a force on its operating button by means of a cam or a lever` It is known that micro switches, in general, are of small size and have, moreover, the special feature of having large current-breaking capacities. However, because of the nature of the mechanism of such a micro switch, a point, in the operational sequence prior to the switching of the contacts, exists at which the movable contact rises off from the stationary contact, and the contact resistance becomes infinite. Accordingly, an important relation exists between the speed of operation and the performance of the micro switch. When the speed at which the operating button is pushed is slow, the electrical life of the micro switch is greatly shortened.

That is, when a micro switch is used as the contact device of a time limit relay, since the speed at which the operating button is pushed is inevitably extremely slow, the disadvantage of this micro switch appears in a magnified form, and as a result, such a relay has heretofore had 3,206,566 Patented Sept. 14, 1965 ICC such disadvantages as extremely short life or as being unusable except at performance below the rated value of the micro switch.

In view of the above-described disadvantages of known relays of this type, it is an object of the present invention to provide a new and improved time limit relay wherein the load on the synchronous motor is substantially reduced, the operational precision is increased, and the operational life is prolonged.

The foregoing object and the other objects of this invention have been achieved by the time limit relay of the invention, in one aspect of which, a disk which rotates together with the indicating pointer of the time limit relay is provided; this cam mechanism only is rotated by the driving power of a synchronous motor, whereby the load on the said motor is reduced, and the operation of the relay actuating mechanism is caused to be smooth; and the relay actuating mechanism is composed by coupling, to the said cam mechanism, an elastic plate which is caused to store elastic energy by the action of an electromagnetic clutch or a separately installed electromagnet and an actuating plate which acts together with a movable contact, whereby the operational precision of the time limit relay is improved and its life is prolonged. According to this invention, instead of use of a micro switch, a contact opening and closing device is composed by using a disk having a cut-out portion and a lever mechanism and such devices as an electromagnet, whereby quick-break and quick-make action of the contacts is constantly obtainable independently of the rotational velocity of the indicating pointer.

The details of the present invention as well as the manner in which the aforestated objects, other objects, and advantages of the present invention may best be achieved will be understood more fully from a consideration of the following description, taken in conjunction with the accompanying illustrations in which the same and equivalent parts are designated by the same reference numerals or letters, and in which:

FIG. 1 is a side elevational view showing the internal construction of an embodiment of the time limit relay according to the invention;

FIG. 2 is a similar elevational view showing the embodiment of FIG. 1 at the time of its operation;

FIG. 3 is a front elevational view showing only the essential construction of the embodiment of FIG. 1;

FIG. 4 is an electrical connection diagram indicating the internal wiring of the embodiment of FIG. 1;

FIGS. 5, 6 and 7 illustrate another embodiment of the invention and correspond respectively to FIGS. l, 2, and 4;

FIG. 8 is a schematic diagram, partly in perspective, showing a modified form of the contact opening and closing mechanism of the time limit relay of the invention;

FIG. 9 is a side elevational View, partly in section, showing a specific embodiment of the arrangement indicated in FIG. 8;

FIG. 10 is a perspective view showing the essential parts of the embodiment of FIG. 9; and

FIG. 11 is an electrical connection diagram indicating the electrical composition of the time limit relay shown in FIG. 9.

' Referring first to FIGS. 1 through 4, the embodiment illustrated therein is constructed as described below. A driving gear 1 fixed to the shaft of a synchronous motor M is enmeshed with a driven gear 3 fixed to a stationary clutch rod 2 of an electromagnetic clutch EC. A trans mission gear 5 fixed to a movable clutch rod 4 of the sai electromagnetic clutch EC is enmeshed with a gear 8 fixe to a rotating shaft 7 of an indicating pointer 6, said ro 4 being so supported that when said clutch EC is excited said rod 4 is attracted leftward (viewed in FIG. 1). A disk 9 having a suitably positioned cut-out part 10 is xed integrally as a single body with the gear 8. An actuating plate 12 which is pivotally supported on and rotates about a pivot 11, separately from the said disk 9, has an actuating lug 13 formed thereon. The lug 13 is adapted to be in abutting contact with the surface of the disk 9 at its cut-out part. A tension spring 14 is connected at one end thereof to a suitable position on the actuating plate 12. An elastic plate of blade spring 15 which produces an elastic force counter to the force of the tension spring 14 is fixed at one end to the actuating plate 12 and has, at its other end, a fork or yoke which is engaged with the aforesaid movable clutch rod 4 of the electromagnetic clutch EC.

Movable plates 16 and 16a are xed to the actuating plate 12 and are provided at their free ends with movable contacts 17 and 17a, which operate, respectively, between stationary contacts 18 and 19 and 18a and 19a. A spiral spring 20 is Xed at its inner end to the rotating shaft 7.

A calibration plate 21 is provided for the aforesaid indicating pointer 6. A setting pointer 2'3 is disposed coaxially with but 4indepedently of the indicating pointer 6 and is rotatably manipulated by a setting knob 22 xed ccaxiallly thereto so as to set the pointer 6.

The electrical system of the above-described embodiment is indicated by the connection diagram shown in FIG. 4. Electric power is supplied from a power source circuit, represented by power source terminals PP and P, to the electromagnetic clutch EC and the motor M, the said clutch EC being connected as shown. The contacts 17, 19, and 18 are connected suitably to controlled equipment (not shown) which is represented by the control :circuit terminals T, Ta, and Tb.

The above-described embodiment has the following operation. In the condition indicated in FIG. 1, it is assumed that the power source is switched ot, and no voltage is impressed on the synchronous motor M and the electromagnetic clutch EC. Accordingly, the stationary clutch rod 2 and the movable clutch rod 4 of the electromagnetic clutch EC are not enga-ged, .and the movable clutch rod 4 is placed in its rest-ored condition by a return spring (not shown) provided in the interior of the said electromagnetic clutch EC.

At this time, furthermore, the actuating plate L2 is placed in its leftwar-d position (as viewed in FIG. l) by the tension of the tension spring 14, whereby the movable contacts 17 and `17a are brought in contact, respectively, with the stationary contacts 18 and 18a, and the actuating lug :13 is made free of a the cut-out part 10 of the disk 9. Moreover, since the elastic plate 115 is pressed and guided toward the right (as viewed in FIG. l) by the movable clutch rod 4, the said plate .115 has no elastic energy stored therein. Accordingly, the contact pressure of the movable contacts 17 and 17a is maintained by only the elastic force of the tension spring 14.

With the relay in the above-described condition, it will now be assumed that the setting pointer 23 provided with the setting knob 22 is set at any `desired time setting, by setting the angular position of the cut-out portion relative to lug 13; and a voltage is impressed on the power source terminals PP and P. The voltage is thereby impressed on the synchronous motor M and the electromagnetic clutch EC, whereupon the rotation Vof the synchronous motor M causes the driven gear 3 provided on the stationary clutch rod 2 of the electromagnetic clutch EC to rotate. Furthermore, this rotation is transmitted to the transmission gear 5 fixed t-o the movable clutch rod 4 to cause rotation of the gear 8, which is enmeshed with this transmission gear 5. On the other hand, the elastic plate 15, which is engaged with the movable clutch rod 4 is caused by the engagement between the stationary clutch rod 2 and the movable clutch rod 4 of the electromagnetic clutch EC to move in the direction of the arrow A in FIG. l, and this elastic plate is thereby caused to store elastic energy. Although this elastic energy produces a force tending to push the actuating plate 12 toward the right as viewed in FIG. 2), the actuating plate retains its original condition since its actuating lug V113 is `abutting, against the disk 9, whereby the movable contacts 117 and 17a are maintained in contact with stationary contacts 18 and 18a, respectively, and the synchronous motor M continues to rotate.

Then, when the preset time h-as elapsed, Iand the indicating pointer 6 has been caused by the rotation of the synchronous motor M to point to the zero point on the calibration plate 21, the cut-out part 1G formed on the `disk 9 coincides with the actuating lug 13 of the actuating plate 12. At this instant, the elastic force, which has heretofore been held, of the elastic plate 15 acts on the actuating plate 12, overcoming the elastic force of the tension spring 14, and causes the actuating plate 12 to rotate counter-clockwise (as viewed in FIGS. 1 and 2) about the pivot 11 as the center of rotation, whereby the actuating lug 13 enters the cut-out part 10. Accordingly, the movable contacts 17 and 17a separate quickly from the stationary contacts 18 and 18a and shift over rapidly to the side ofthe stationary contacts 19 and 19a. Simultaneously, the rotation of the synchronous motor is stopped. In this condition of the relay at this stage of operation, which is shown in FIGS. 2 and 3, the electromagnetic clutch EC is still operating as will be understood from FIG. 4, thereby maintaining the elastic force of the elastic plate 15 and the contact pressure of the movable contacts 17 and 17a.

At the subsequent time setting, when the power source represented by the terminals PP and P is switched off, the magnetic clutch EC is restored and the pointer 6 is returned to the previous presetting or initial position by the return elastic force of the spiral spring 20. Thereafter, the same procedures and operation as described above are repeated. Accordingly, by connecting a controlled item of equipment (not shown) suitably t-o a control circuit as represented by T, Ta, and Tb of FIG. 4, it is possible to cause operation during a predetermined time interval or to cause operation after .a predetermined time interval.

In the modification illustrated in FIGS. 5, 6, and 7, the elastic plate 1,5 fixed to the actuating plate 12 is so adapted that its extreme end confronts the electromagnetic iron core 24 of an electromagnet EM which is provided separately from the electromagnetic clutch EC. Electrically, this electromagnet EM is connected in parallel with the electromagnetic clutch EC as indicated in FIG. 7. Accordingly, the electromagnet EM operates and returns simultaneously as the electromagnetic clutch EC.

The operation of this modiiication is similiar to that 'of the embodiment described in connection with FIGS. 1 through 4 with the difference that the maintaining of the elastic lforce `of the elastic plate 15 is accomplished by the electromagnetic force of a separate electromagnet EM.

As described above, in one of its embodiments, the present invention provides a relay operating mechanism wherein the elastic force of an elastic plate 15 which actuates an actuating plate 12 is stored by the electromagnetic force of an electromagnetic clutch EC or a separately provided electromagnet EM, and snap action is effected by the cooperative action of an actuating lug 13 of an actuating plate 12 and a disk 9 having a cutout part 10. Moreover, since this mechanism does not require `direct driving power of a synchronous motor for its relay operation, it is possible to use la synchronous motor rof small size. Furthermore, the present invention provides a time limit relay of high performance which has reliable oper-ation and long life without the use of high-priced micro switches or other quick-break, quickmake switches.

Another embodiment of the invention wherein a modied form of the contact opening and closing mechanism is used is illustrated in FIGS. 8 through 11.

Referring first to FIG. y8, a rotating shaft 7, to which the inner end of a spiral spring 20 is fixed, has also lixed thereto an indicating pointer 6, a driven gear 8, and disk 9 which has a cut-out part 10. A lug 13 at the end of an actuating lever 30 which rotates together with an actuating plate 12 about a pivot 11 is in abutting contact with the disk 9. An actuating spring 31 is fixed at its movable end to the actuating plate 12, imparting a torque thereto which tends to rotate an integrally rotating combination comprising the actuating plate 12, the actuating lever 30, and a movable plate 16 in the counter-clockwise direction (as viewed in FIG. 8). Accordingly when the cut-out part 10 of the aforesaid disk 9 coincides with the lug 13, the elastic force of the spring 31 causes the contacting condition of the movable contact 12 of the movable contact plate 16, which moves together with the actuating plate 12, to be switched over in a quick-break, quick- -motion manner. When the magnetic forces of the electromagnetic clutch EC and the electromagnet EM are removed, the elastic force of a return spring 32 is released to act, by way of a movable iron member 34 rotatably pivoted at a pivot 33, on the actuating plate 12, thereby disengaging the lug 13 from the cut-out part 10, against the counterforce of the aforesaid actuating spring 31 and, at the same time, rotating the actuating plate 12 and causing the contact 17 to be reset in a quick-break, quickmotion manner.

A practical embodiment of the principle indicated in FIG. 8 will now be described below with reference to FIGS. 9, 10, and 11. As in the case of the embodiments described hereinbefore, the rotational power of a synchronous motor M is transmitted through an electromagnetic clutch EC and by way of a gear 5 to rotate a rotating shaft 7. An actuating plate 12 is fixed to a pivotal shaft 11 and rotates together with an actuating lever 30, which is also fixed to the pivotal shaft 11. The movable end of an actuating spring 31 which imparts torque to the actuating plate 12 and the actuating lever 30 is fixed to the actuating lever 30. For the return spring 32 which imparts a torque counter to the abovesaid torque, the return spring of a moving-iron type electromagnet is used, and this moving-iron member 34 is caused by the spring 32 to be in positive contact against the actuating plate 12. Stationary contacts 18 and 19 are so mounted on a contact support base 35 as to confront a moving contact 17 on its opposite sides. The moving Contact 17 is fixed to and rotates with the pivotal shaft 11. As in the case of the previously described embodiments, a setting pointer 23 which is fixed to an independent shaft and is set manually by means of a setting knob 22 is disposed coaxially with and confronting the indicating pointer 6, the reset position of which, that is, the time limit, is set mechanically by the setting pointer 23 by way of its contacting lug 36. The rotational positions of the pointers 6 and 23 are indicated on a calibration plate 21.

The electrical composition of this time limit relay is as indicated by the connection diagram of FIG. ll.

In this electrical arrangement, a rectiiier Se is connected across the power source terminals P and PP to supply activating direct current to the electromagnetic clutch EC and the electromagnet EM, which are connected in series.

The operation of the embodiment described above will now be described below. When this time limit relay is in its condition wherein power thereto is cut olf, the synchronous motor M is inoperative, the electromagnetic clutch EC is in its reset condition, and the electromagnet EM is also in its reset condition. Accordingly, the moving-iron member 34 is caused to press against the actuating plate 12 by the return spring 32, thereby imparting to the said actuating plate 12 a torque overcoming the torque due the actuating spring 31 and causing the movable contact 17 to press against the stationary 18, In this condition of the relay, the lug 13 of the actuating lever 30 is in a position freely clear of the cut-out part 10 of the arrangements utilizing micro switches, a synchronous mo- 6 disk 9, and the torque imparted by the spiral spring 20 to the rotating shaft 7 is causing the indicating pointer 6 to press against the lug 36 of the setting pointer 23. The above-described condition is shown particularly in FIGS. 8 and 10.

If the appropriate voltage is now impressed on the power source terminals P and PP, the synchronous motor M will rotate, and at the same time, the electromagnetic clutch EC and the electromagnet EM will be activated by the direct current which has been rectified by the rectifier Se. Consequently, the gear 5 will rotate to cause the rotating shaft 7, the disk 9, and the indicating pointer 6 to rotate, thus winding the spiral spring 20. Since the electromagnet EM is activated at this time, the movingiron member 34 is drawn apart from its pressing contact with the actuating plate 12. However, the lug 13 of the actuating lever 30 will be pressing against the periphery of the disk 9. Accordingly, the rotation of the actuating plate 12 'will be stopped, and the movable contact 17 will be maintained in contact with the stationary contact 18.

When, after the predetermined time limit has been reached, and the disk 9 has rotated to a position where its cut-out part 10 coincides with the lug 13, the lug 13 enters the cut-out part 10, and the actuating plate 12 is caused by the tensile force of the actuating spring 31 to rotate rapidly. Consequently, the movable contact 17, which is supported on the same shaft 11 as the actuating plate 12, is caused to quickly break its contact with the stationary contact 18 and to make its contact with the opposite stationary contact 19.

Although the synchronous motor is stopped by this breaking of the contact between the contacts 17 and 18, the contacting device and other parts are maintained in their operating condition and electrically control other equipment.

If the power source is removed, the electromagnet EM will be placed in its restored condition. Consequently, the moving-iron member 34 will be caused by the return spring 32 to rotate the actuating plate 12 rapidly, overcoming the force of the actuating spring 31, thereby switching the movable contact 17 from the contact 19 to the stationary contact 18 and, at the same time, causing the lug 13 to disengage from the cut-out part 10. Accordingly, the rotating shaft 7 will be rotated by the elastic torque of the spiral spring 20, and all parts will be returned to their respective conditions prior to operation.

It will be seen that the above-described embodiment, similarly as in the case of the preceding embodiments, accomplishes switching of contacts in a quick, positive manner, which affords long life of the contacts. Moreover, since this embodiment obviates the necessity of pressing on an operation button, as in the case of conventional tor of relatively low driving power suliices, and an electromagnetic clutch of small size may be used, whereby a time limit relay of substantially miniature size is afforded.

Since it is obvious that many changes and modifications can be made in the above-described details without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited to the details described herein except as set forth in the appended claims.

What is claimed is:

1. A timer device comprising, in combination, a control circuti having two sets of stationary contacts, a rotatably driven disk having an aperture, a synchronous motor for driving said disk, an electromagnetic clutch comprising means selectively coupling said motor and said disk, a snap-action switch comprising a pivotally mounted plat having electrical contacts thereon and operable to tw positions alternatively making contact with said two set of stationary contacts, means of said plate engaging sai disk during rotation disposed for insertion into said cut out portion when the angular position of said cut-out por tion corresponds therewith thereby holding the contacts on said plate spaced from one of said two sets of contacts during rotation of said disk in the absence of coincidence with said cut-out portion and for permitting said contacts on said plate to be snapped into contact with said one set of stationary contacts when coincident with said cut-out portion, means constantly urging said plate toward the other of said two sets of stationary contacts in a direction for causing said contacts on said plate to make contact with said other of said two sets of contacts, means for selectively biasing said plate toward said one set of stationary contacts during rotation of said disk in opposition to the last mentioned means, means operable during nonrotation of said disk to selectively set the angular position of said cut-out portion relative to said means on said plate to variably set the interval during which the contacts on said plate are held spaced from said one set of stationary contacts, an indicating pointer rotatable with said disk, and a return spring operably connected to said disk to return said disk and pointer to an initial position when said clutch is in a de-energized condition.

2. A timer device comprising, in combination, :a control circuit having two sets of stationary contacts, a rotatably driven disk having a cut-out portion, a synchronous motor for selectively rotatably driving said disk, an electromagnetic clutch comprising means selectively coupling said motor and said disk, :a snap-action switch comprising a pivotally mounted actuating plate having electrical contacts thereon operable to two positions alternatively making contact with said two sets of stationary contacts, a blade spring biasing said actuating plate selectively in a direction causing the contacts thereon to make contact with one of said two sets of stationary contacts, means on said plate engaging said disk during rotation disposed for insertion into said cut-out portion when the angular position of said cut-out portion corresponds therewith thereby holding the contacts on said plate spaced from Said one set of stationary contacts during rotation of said disk in the absence of coincidence with said cut-out portion and for permitting said contacts on said plate to be snapped by said blade spring into contact with said one set of stationary contacts when coincident with said aperture, spring means constantly urging said plate toward the other of said two sets of stationary contacts, said blade spring having a portion operably connected to said electromagnetic clutch for developing elastic energy in said blade spring biasing said actuating blade when said electromagnetic clutch is in energized condition, means operable during non-rotation of said disk to selectively set the angular position of said cut-out portion relative to said means on said plate to variably set the interval during which the contacts on said plate are held spaced from said one set of stationary contacts, an indicating pointer rotatable with said disk, and a return spring operably connected to said disk to return said disk and pointer to an initial position when said clutch is in a `de-energized condition.

3. A timer device comprising, in combination, a con trol circuit having two sets of stationary contacts, a rotatably driven disk having a cut-out portion, a synchronous motor for driving said disk, an electromagnetic clutch comprising means selectively coupling said motor and said disk, a snap-action switch comprising a pivotally mounted actuating plate having electrical contacts thereon operable to two positions alternatively making contact with said two sets of stationary contacts, a blade spring selectively biasing said actuating plate in a direction causing the contacts thereon to make contact with one of said two sets of stationary contacts, means on said plate engaging said disk during rotation disposed for insertion into said cutout portion when the angular position of said cut-out por tioncorresponds therewith thereby holding the contacts on said plate spaced from said one set of stationary contacts during rotation of said disk in the absence of coincidence with said cut-out portion and for permitting said contacts on said plate to be snapped by said blade spring into contact with said one set of stationary contacts when coincident with said cut-out portion, spring means constantly urging said plate toward the other of said two sets of stationary contacts, an electromagnet selectively ener gizable and operably connected to said blade spring for storing energy therein and causing it to bias said actuating plate toward said one set of stationary contacts when said electromagnet is in an energized condition only, means operable during non-rotation of said disk to selectively set the angular position of said cut-out portion relative to said means on said plate to variably set the interval during which the contacts on said actuating plate are held spaced from one set of stationary contacts, an indicating pointer rotatable with said disk, and a return spring operably connected to said disk to return said disk and pointer to an initial position when said clutch is in a de-energized condition.

4. A timer device comprising, in combination, a control circuit having two sets of stationary contacts, a rotat ably driven disk having a cut-out portion, a synchronous motor for driving said disk, an electromagnetic clutch comprising means selectively coupling said motor and said disk, a snap-action switch comprising a pivotally mounted plate having electrical contacts thereon operable to two positions alternatively making contact with said two sets of stationary contacts, means comprising a pivotally mounted member selectively biasing said plate in a direction causing the contacts thereon to make contact with one of said two sets of contacts, means on said plate engaging said disk during rotation disposed for insertion into said cutout portion when the angular position of said cutout portion corresponds therewith thereby holding the contacts on said plate spaced from said one set of contacts during rotation of said disk in the absence of coincidence with said cut-out portion and for permitting said contacts on said plate to be snapped into contact with said one set of stationary contacts when coincident with said cut-out portion, a spring constantly urging said plate toward the other of said two sets of stationary contacts, Said means for selectively biasing said plate toward said one set of stationary contacts during rotation of said disk comprising an electromagnet energizable to cause said pivotally mounted member to act in opposition to the last mentioned spring, means operable during non-rotation of said disk to selectively set the angular position of said cutout portion relative to said means on said plate to variably set the interval during which the contacts on said plate are held spaced from said one set of stationary contacts, an indicating pointer rotatable with said disk, and a return spring operably connected to said disk to return said disk and pointer to an initial position when said clutch is in a de-energized condition.

References Cited by the Examiner UNITED STATES PATENTS 2,302,260 l1/ 42 Rothwell et al 200-38 2,891,617 6/ 59 Wharton 200-38 2,946,902 7/ 60 Hagen 20G-38 2,964,933 12/ 60 Fritz 200--38 3,095,485 6/63 Rowe 200-38 BERNARD A. GILHEANY, Primary Examiner, 

1. A TIMER DEVICE COMPRISING, IN COMBINATION, A CONTROL CIRCUIT HAVING TWO SETS OF STATIONARY CONTACTS, A ROTATABLY DRIVEN DISK HAVING AN APERTURE, A SYNCHRONOUS MOTOR FOR DRIVING SAID DISK, AN ELECTROMAGNETIC CLUTCH COMPRISING MEANS SELECTIVELY COUPLING SAID MOTOR AND SAID DISK, A SNAP-ACTION SWITCH COMPRISING A PIVOTALLY MOUNTED PLATE HAVING ELECTRICAL CONTACTS THEREON AND OPERABLE TO TWO POSITIONS ALTERNATIVELY MAKINGCONTACT WITH SAID TWO SETS OF STATIONARY CONTACTS, MEANS OF SAID PLATE ENGAGING SAID DISK DURING ROTATION DISPOSED FOR INSERTION INTO SAID CUTOUT PORTION WHEN THE ANGULAR POSITION OF SAID CUT-OUT PORTION CORRESPONDS THEREWITH THEREBY HOLDING THE CONTACTS ON SAID PLATE SPACED FROM ONE OF SAID TWO SETS OF CONTACTS DURING ROTATION OF SAID DISK IN THE ABSENCE OF COINCIDENCE WITH SAID CUT-OUT PORTION AND FOR PERMITTING SAID CONTACTS ON SAID PLATE TO BE SNAPPED INTO CONTACT WITH SAID ONE SET OF STATIONARY CONTACTS WHEN COINCIDENT WITH SAID CUT-OUT 